Careful integrity management has helped to ensure that many pipelines installed in the 1980s continue to function at their maximum capacity. Roberto Bruschi, vice-president of sealines and subsea at Saipem, explains what must be done to enable today’s larger and deeper pipelines to last just as long, and the challenges encountered in the sustainable development of the offshore pipeline industry.
Operators and developers are studying, planning and constructing almost 5,600 miles (9,012km) of offshore oil and gas pipelines, with the most active regions being Europe, the Middle East, the South Pacific and the Gulf of Mexico. While the largest project in Europe is the South Stream pipeline, which would move Russian gas through the Black Sea to Bulgaria and other markets through a 560-mile (910km), 32in pipeline to be installed in waters as deep as 7,300ft (2,225m), it’s Asia and the Middle East that have the biggest ambitions, with the South Asia Gas Enterprise (SAGE) pipeline project. Its developers propose to move natural gas from the Oman Middle East Compression Station (MECS) to Gujarat, India, through an 807-mile (1,299km) pipeline of 24-27in pipe in the Arabian Sea, in water depths of up to 11,100ft (3,383m).
These and other ultra-deepwater projects, which propose to use pipe diameters greater than those that have ever been used before at such depths – and install them over long lengths of pipe far offshore – pose technological challenges for offshore pipeline contractors, but are not the only challenges the fast-growing offshore oil and gas industry is facing. Indeed, not only are contractors faced with building more complex pipe-laying and field development vessels for the new pipelines set to come into service over the next few years, but they also need to ensure that pipelines built decades ago are functioning to their optimum capacity, and that their engineers and technicians will be able to meet the future challenges that are sure to come as technology evolves further.
Today’s technological challenges: Saipem’s response
Saipem, one of the world leaders in pipeline engineering, procurement, project management and construction, and a particular expert in the design and execution of large-scale onshore and offshore projects, will likely be involved in some of the oil and gas sector’s most challenging offshore projects in the coming years. These include the SAGE pipeline project, as well as the South Stream pipelines and the gas export trunklines from the presalt region approximately 300km off the coast of São Paulo, both of which will be installed in water depths of up to 2,200m.
But, despite the technological complexity of these ambitious projects, Saipem is ready.
"In fact, when we designed the Castorone [the biggest pipelayer vessel in the world, which can perform S-lay in shallow waters and steep S-lay in deepwater, switching to J-lay mode for ultra-deepwater], we were thinking specifically of the SAGE project," says Roberto Bruschi, vice-president of sealines and subsea at Saipem. "Obviously, this project is challenging – because of its depth, length and the fact that the route is not close to the land – but our vessels are able to do it."
This is because of the huge range of distinctive features the Castorone offers, including a DP-3 dynamic positioning system designed for pipelay, a high bollard pull to counteract pipe bottom tension and an articulated stinger (external ramp) capable of attaining a near-vertical ramp exit angle.
The vessel’s lay equipment is able to allow for continuous control of overbend stresses in the pipe through different conditions and in different environments. The stinger comprises three articulated, adjustable sections, enabling a change of set-up from shallow to ultra-deepwater, without having to abandon the pipe.
"Not only is the stinger large and long, it is also smart, which means you know exactly what is happening at each point, confirming that you are not threatening the integrity of the pipeline or of the stinger itself," says Bruschi.
When it comes to field development, Saipem’s FDS-2, which was launched at the end of 2011, is equally state of the art.
"I believe this is the most powerful vessel for field development in terms of efficiency and from the business point of view," Bruschi stresses.
The FDS-2 is an advanced DP multipurpose vessel, equipped with a J-lay tower capable of laying up to 36in-diameter pipelines in deepwater. Its crane can lift up to 1,000t and its J-lay tower, designed to lay quadruple joints, has a capacity of 2,000t. Among other projects, this vessel will be used for the Rota Cabiunas, which is a 236-mile (380km) pipeline with a 24in diameter.
Pipeline integrity management: keeping yesterday’s pipelines up to date
It’s not just the laying of new pipelines that contractors like Saipem need to be concerned with; another challenge for these companies is ensuring that pipelines installed as long ago as the 1980s continue to function at their maximum capacity. For Saipem, this includes pipelines such as the Trans-Mediterranean pipeline system, three 20in pipelines constructed between 1978-83 to bring natural gas from Algeria to Italy, the deepest subsea pipeline installation at the time, as well as two 26in pipelines laid in the early 1990s to improve export capacity from North Africa.
Prior to this, worldwide experience in the design, construction and maintenance of offshore pipelines was limited to water depths of 150m, but the Trans-Mediterranean pipeline was installed in water depths of up to 615m in 1980.
Fast-forward more than 30 years and the pipeline is still in operation, largely thanks to the Trans-Mediterranean Pipeline Company’s (TMPC’s) careful pipeline integrity management systems, engineered by Saipem.
"In order to guarantee pipeline integrity over the asset’s design lifetime, it is essential to carry out pipeline integrity management carefully," Bruschi emphasises. "At Saipem, particular care is taken over this."
This involves, among other things, yearly visual inspections at the most critical points, intelligent pigging on a regular basis (the time interval depending on the fluid transported) and the continuous updating of a database with absolutely every piece of information relevant to the project.
"All of this information is used to decide whether the pipeline is OK to continue operation or if it needs to stop and be analysed in detail," Bruschi explains. "But, in order to do this, you need to have all the information on what has been done year by year; that information can then be used to repair a problem. You can only do this if you have a regularly updated database."
Tomorrow’s issues: industry collaboration essential to success
Bruschi has been working in the offshore field for 33 years and, therefore, is aware of the importance of collaboration between contractors like Saipem, industry and academia in ensuring that the offshore oil and gas sector advances as quickly and sustainably as possible, allowing the continuing construction of state-of-the-art pipelines in the years to come.
"It is important that a company like Saipem is engaged in this kind of collaboration – with companies, with the academic world, with the oil and gas industry – particularly to ensure that our technicians are able to solve issues day by day on a ship," he says. "You cannot wait for information to come from a consultancy group; you need to have this kind of capacity within the company.
"Moreover, memory is important; it’s an important role that the experienced play – to transfer knowledge to the younger generation. It’s essential that they start from where their predecessors left off. One of the issues within the offshore industry is a loss of competence when people change and generations change; if you lose key people, you can have problems. Therefore, the diffusion of a ‘knowledge management’ culture is essential to the future of the industry."